`[[NSBundle mainBundle] bundleIdentifier]` is nil when running XCTest

Question

Even when it is defined in the "...Tests" target Info.plist, the identifier remains nil. I need it to have a valid value for a third party lib.

Answer 1

This is because unit tests don't load your application bundle or even the unit test bundle as the main bundle.

For more info on this see

• NSURL to file path in test bundle with XCTest
• XCTest fails when calling [NSBundle mainBundle]

Now we can hack around this by including a category on NSBundle in your unit test project. The Objective-C category hack also works for swift unit tests because Bundle is bridged to NSBundle, just make sure you have a bridged header for your unit test project.

You can then have it search for the correct main bundle, but if you just want a quick and dirty way to have a valid bundle identifier then use the following

@interface NSBundle (BundleIdentifier)

-(NSString *)bundleIdentifier;

@end

@implementation NSBundle (BundleIdentifier)

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wobjc-protocol-method-implementation"
-(NSString *)bundleIdentifier
{
    return @"com.yourcompany.yourapp.unitTests";
}
#pragma clang diagnostic pop

@end

Now all that is left is to include the header file in your unit test so that the category loads up.